1. Field of the Invention
The present invention relates to an electric contact disposed between a first electrical part and a second electrical part for electrically connecting them, and also relates to a socket for an electrical part provided with such electric contact.
2. Related Art
A prior art provides a socket for an electrical part provided with an electric contact disposed between a first electrical part and a second electrical part so as to electrically connect them. For example, there has been provided a socket for an electrical part, which is provided with a socket body disposed on a printed circuit board and accommodated with an electrical part, in which the printed circuit board and the electrical parts are electrically connected through a plurality of electric contacts or contact pins disposed to the socket body. In a structure in which the electric contact has a terminal side contact member contacting a terminal of the electrical part and a substrate side contact member contacting the printed circuit board, a coil spring is disposed so as to form a close winging portion between the terminal side contact member and the substrate side contact member for shortening the electrical connection therebetween.
One example of the socket for an electrical part provided with such electrical contact having a coil spring is disclosed in Patent Publication 1 (Japanese Patent Publication No. 3326095). In this Patent Publication 1, there is shown “a socket for an electrical part including a contact provided with a terminal side contact member contacting a terminal of an electrical part, a substrate side contact member contacting a printed circuit board, and a coil spring urging the terminal side contact member and the substrate side contact member in a direction separated from each other, the coil spring being provided with a first spring portion abutting against the terminal side contact member, a second spring portion abutting against the substrate side contact member, and a close winding portion disposed between the first and second spring portions and wound up at the minimum pitch.”
There is also disclosed in this Patent Publication 1 that “according to this structure, an electric signal is transmitted through the close winding portion, so that the electric signal may flow along an axial direction of the coil spring at the close winding portion, and accordingly, an increasing in inductance and resistance due to the flow of the high frequency electric signal in a coil-shape at a rough winding portion can be prevented from causing, thus achieving reduction of inductance and resistance”.
However, in the invention disclosed in the Patent Publication 1, since the close winding portion is provided between the first and second spring portions, it is difficult to realize a structure in which an axis of the first spring portion inclines with respect to an axis of the second spring portion so that the terminal side contact member is inclined.
Therefore, in a case where the axis of the terminal of the electrical part is shifted from the axis of the terminal side contact member, the terminal side contact member does not follow the shifting of the terminal of the electrical part, which may result in fault in electric connection between the electrical part and the printed circuit board.